What did I learn today?

• The ropa vieja platter at Cafecito in Chicago is delicious, but now I am really over-full. Shouldn’t have eaten it all I guess.
• Cyclic but not periodic…. Heard a talk by Yuliy Baryshnikov on “scribbles and doodles” — extracting information from the noise of data, not just the main features. Cool ideas (keep in mind this is an intellectual exercise here of recalling what I can without looking at my several pages of notes): the shape of the noise in data is itself important. We model financial time series as Brownian motion with drift, right, but we know it’s not exactly that. Look at the up-turns and down-turns of a random walk, look at persistence diagrams; you can tell apart Brownian motion and real financial data. I think I’m getting too tired to write this up well. Next part of the talk was about cyclic but non-periodic time series data.
• Talk by Katharine Turner on cone fields — using vector fields to reconstruct a manifold from a set of sample points/point cloud, for instance. I am curious about seeing this in action — some clever ideas for dealing with corners and furry data.
• Sayan Mukherjee: butterflies and dogs. I mean, Grassmannians and Stiefel manifolds. Looking at Grassmannians Gr(k,n) with different k, because what if your underlying manifold is a union of linear subspaces of different dimensions? Fun to see Stiefel manifold in this context, in a talk by a statistician!
• Omer Bobrowski: random geometric complexes. Some interesting things about Cech complexes, for instance. I need to think about this and how it relates to the algebraic geometry I learned in grad school.

More sleep will help more intelligent conversation. I believe there is now a family of three in the closet-sized hostel room next to me, and it turns out angry tw0-year-olds are louder than sleepy Singaporean teenaged tourists. But I have earplugs 🙂